Found this in the Village Voice's NYC Guide:
"Diamond Dairy Restaurant, 4 W 47th St, New York, NY 10036, West Side
Phone: (212) 719-2694, Price: $
Jewish, 42nd to 59th, Restaurants - General, Restaurants
Dramatically poised on a balcony above the National Jewelers Exchange, this old-fashioned Ashkenazic Jewish dairy restaurant features the usual dishes including blintzes, puddings, and rivers of sour cream. Baked fish is a particular specialty, but even better is cholent, a garlicky bean stew. All hail the orange kugel floating on top! Enjoy watching the jewelry transactions down below as you dine, and go as soon as possible, before this New York institution goes the way of Dubrow's and Hammer's."
It sounds like it's a throwback to Dubrow's. I'll have to check it out next time I'm in NYC.